Frequency multiplier system



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G. H. TAYLCR, JR

FREQUENCY MULTIPLIER SYSTEM Filed April 22, 1944 y ma E m m, M m 7 a A 5 w ww Y BW 2 Nkwa d Smm m w SSQNNK H v Q Patented Jan. 31, A195() ITE!) STATES OFFICE 4 Claims.

My invention relates broadly to communication systems and more particularly to a radio communication system having a high degree of selectivity permitting the efficient utilization of the available frequency spectrum.

One of the objects of my invention is to provide a system of radio communication for transmitting and receiving` a particular type of high frequency energy and arranged to overcome the difficulties caused by side bands which normally interfere with efficient communication.

Another object of my invention is to provide an improved circuit arrangement for a frequency multiplier system operating on a linear law.

Still another object of my invention is to provide a frequency multiplier circuit employing a frequency modulated oscillator associated with a mixer circuit and including a pair of independently tunable circuits coupled with the output system of the frequency modulated oscillator for effecting linear law frequency multiplication.

A further object of my invention is to provide a circuit for a frequency modulated controlled frequency multiplier as set forth in the specification hereinafter following by reference to the ac companying drawing which illustrates one of the methods I employ for effecting linear law frequency multiplication without undesired frequencies in the system of my invention.

The circuit diagram illustrates a form of circuit which may be employed in a transmission system. The input circuit constituted by transformer 22 connects to a linear law frequency multiplier circuit which is a frequency modulated controlled frequency multiplier. comprises an arrangement of tubes represented at |05, |06 and |07. Tube |05 is a modulator embodying cathode |05a, inner grid |051), screen grid i05c, control grid |0511 and anode |05e. The bias on control grid |05d is regulated by the arrangement of cathode resistor |06. The input circuit from transformer 22 connects between control grid |05d and cathode |05a. The output circuit is supplied with positive potential from the positive bus indicated at |01'. The potential supply for the output circuit is completed from the negative side of the B potential source to bus |08 to cathode |05a as shown. An electron coupling is provided between the modulator |05 and the input circuit of the frequency modulated oscillator shown at |06 by means of the connection of the control grid |0601 of tube |06 through condenser |09 to the inner grid |0517. The cathode of the frequency modulated oscillator |06 connects to the bus |08 forming the opposite i side of a portion of the output of modulator tube |05.` Atuned coupling circuit is interposed between the output of modulator and the input of the frequency modulated oscillator |06. Suitable bias is maintained on control grid |06d The multiplier through resistor ||2. The anode |06e of the frequency modulated oscillator |06 is connected in circuit with the series connected inductances H4, ||5 and ||6 to the positive bus |01 to which the output of modulator |05 also connects. Inductance ||6 is coupled with the inductance forming part of the tuned circuit Frequency modulated energy is thus fed back from the output circuit of the frequency modulated oscillator |06 to the input circuit through the series path constituting inductances ||4, ||5 and ||6 establishing energy which might be designated Ffmos with respect to the applied energy at the transformer input circuit 22. The tube|06 has its output circuit coupled through two separately tuned channels H6 and leading to the inner grid |0'Ib and the control grid |0717l of the -mixer tube |01. The mixer tube |01 includes cathode 01a, inner grid |0112, shield l'lf, control grid |0'ld and anode |0le. Anode |0'|e connects through tuned circuit ||`|"A to the positive bus |01 and provides means for connection of the output coupling circuit indicated at ||8 thereto for delivering output energy at frequency f. The required bias potential is supplied to the control grid |0'ld through the biasing circuit H9. The required potential is applied to shield grid |0`|f through resistor |20. The energy transferred from winding ||5 to tuned circuit` maybe designated Ffmosc while the energy transferred from winding ||4 to tuned circuit ||6 for vimpression upon control grid |0111 may be designated 771 Ffmasc n tilnesf plus Ffmoac) These frequencies are mixed in the circuits of tube |01 producing in the output tuned circuit 1 a frequency nX(n times delivering to the output circuit |8 energy of frequency f as compared to the input frequency of In the diagram, circuit is tuned to any oscillating frequency. Circuit is tuned to the same frequency as circuit Circuit ||6 is tuned to the desired component of the frequency modulation side-band frequency, which is some multiple of the fundamental modulation frequency `of the circuit plus the oscillator frequency.V Circuit |1 is tuned to the desired multgiple 'orharmonic of the input frequency to circuit 22. The circuit of my invention operates as follows: the pentode grid-cathode capacity is varied by the changes in mutual conductance caused by the input voltages. These variations of interelectrode capacity are utilized to frequency-modulate the triode oscillator. The Nth side-band term of the frequency modulation sideband containing the desired harmonic is selectively fed to the output hexode mixer. The oscillator frequency is mixed in the hexode with this side-band component, producing` the difference frequency which is the desired harmonic of the input frequency to the pentode. The Bessel function of the Nth term of a frequency modulation side frequency is linear as to amplitude with relation to the amplitude of the modulating frequency. In the circuit of my invention the f/n input is used to frequency modulate any high frequency oscillation. This becomes carrier plus-or-minus f/n plus-or-minus 2li/TL plus-orminus 3fm plus--or-minus nf/n. The desired component of the side frequency, i. e. carrier plus nf/n is mixed with carrier in the hexode, giving vif/1i or f output which has been derived from f/n. The side-bands in the above are spaced n times their respective distances in the output as in theinput, if more than one modulating frequency is fed to the input.

I have explained my invention in one of its preferred embodiments but I am fully aware that modifications of the circuit may be made and I intend no limitations upon my invention. I desire that it be understood that various modiflcations of the circuit and principles of operation explained herein shall be included within the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. A frequency multiplier comprising a source of high frequency energy, a modulator including` an electron tube having a cathode, inner grid, screen grid, control grid and anode electrodes, a circuit extending between said source and said control grid and cathode electrodes, an output circuit including said anode, screen grid and said cathode, a frequency modulated oscillator including a cathode, control grid, and anode, a tunableV input circuit connected between said last mentioned control grid and said last. mentioned cathode, an output circuit for said frequency modulated oscillator connected between the anode thereof and said last. mentioned cathode, independent inductively coupled circuits connected in the outputcircuit of said frequency modulated oscillator, means for coupling the input and output circuits of said frequency modulated oscillator, connections between said last L of said grid electrodes and energizing all of said cathodes and each of said output circuits.

2. A frequency multiplier comprising a source ofy high frequency energy, a modulator including an-electron tube having a cathode, inner grid, screen grid, control grid, and anode electrodes,` a

circuit extending between said source and said control grid, and cathode electrodes, an output circuit including said anode, screen grid, and cathode, a frequency modulated oscillator including a cathode, control grid, and anode, a tunable input circuit connected between the control grid and cathode of said frequency modulated oscillator, an output circuit coupled with said tunable circuit and extending between the cathode and anode of said frequency modulated oscillator, a pair of tunable circuits connected in said output circuit, an electron coupling between the tunable input circuit of said frequency modulated oscillator through the inner grid and cathode of said modulator, a mixer tube including a cathode, inner grid, control grid, screen grid, and anode, a pair of input circuits extending between said last mentioned tunable circuits andy the inner grid and cathode and the control grid and cathode respectively of said mixer tube, a tunable output circuit connected between the anode and cathode of said mixer tube, and means for predetermim ing the potential of each of said grid electrodes and energizing all of said cathodes and each of said output circuits.

3. A frequency multiplier comprising a source of high frequency energy, an electron tube inodulator connected with said source, an electron tube frequency modulated oscillator having coupled input and output circuits, al pair of independently tunable branch circuits disposed in said output circuit of said frequency modulated oscillator, means electronically coupling the input circuit of said electron tubel frequency modu lated oscillator with said electron tube medulator, a mixer tube including a cathode and anodeY one of said grid electrodes and the associated cathode, a separate circuit connection between another of said grid electrodes and another of said branch circuits with the associated cathode, a tunable output circuit connected between the anode and cathode of said mixer tube, and means for energizing the circuits of said modulator, frequency modulated oscillator and said mixer tube.

4. In a linear law frequency multiplier circuit, a modulator, a frequency modulated oscillator electronically coupled with said modulator, a mixer circuit having a pair of independently tunable circuits ccupled with the output system of said frequency modulated oscillator, a separately tunable circuit connected with the output of said mixer circuit and an output circuit coupled With said separately. tunable circuit.

GEORGE H. TAYLOR, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,911,850 San'deman et' al. May 30, 1933 1,957,885 Grimwood May 8, 1934 2,117,739 Miller May 17, 1938 2,159.595 Miller May 23", 1939 2,176,526 Friend Oct. 17, 1939 2,220,689 Shore Nov. 5, 1940 2.230,232 Crosby Feb. 4, 1941 21,299.059 Sandor Oct. 13, 1942 2,361,606 Crosby Oct. 31, 1944 

